User interfaces allow a human user to interact with a system or device and thereby control and/or receive feedback from the system or device. Examples of this broad concept include the interactive use of an operating system on a computing device. The design of a user interface may affect the usability of the system, such as an amount of effort a user expends to effectively control the system and to receive feedback from the system. A graphical user interface (GUI) is a form of user interface that can both accept user input and provide a graphical output to a display.
Because GUIs output on presence-sensitive displays of mobile computing devices are typically small and compact, the use and operation of such GUIs is prone to input errors, for example, when a user attempts to select an object located on a very small or crowded region within a GUI. Reducing input errors can improve the speed and efficiency of GUI operations and improve the user experience by reducing user frustration resulting from inadvertent actions.